I'm currently working on a new Tower Ladder fire truck that I just recently got into game successfully, my issue is after I made an extra as the ladder raised and extended all the way up with a Collision.. the Wheels are gone the doors won't open, and you can walk through the truck but get stuck. I'm not sure if my issue is that I set up the COL's somehow, ( extra_2 - extra_2 [COL] ) or if its because I have a Collision spanning about 100' over the truck.. I would really like to get this to work, if anyone could help me out I would greatly appreciate it, here are some pictures:

Do your Collision models have standard e and mass values? Also i have similar problem i explained in my post below where after export vehicle doesn't have wheels, it's out of control sliding around and you can't enter it. If I re-export same file without any changes, it gets fixed. This happens to me totally random.

I Haven't set any value for e but I did mess with the mass value wondering if maybe the wheels were breaking due to the COLs possibly being too heavy, that didn't fix anything but yeah I never set a value for e, mass is set to 0.5 to test out if it was too heavy..

and I can also report that wheel issue but its only happened to me on this specific model.

No no I believe I am wrong, because E and mass values seems to be set automatically in the last versions of ZM. But I do have export issues, when sometimes my vehicle has no wheels I can't enter it and it floats above the ground, then I re export same file without any changes and it's suddenly all fine. I also had other Collision problems which I don't think it had similar defects and that was a related to making separate Collision pieces like some original GTA V trucks have. So other than that hopefully Oleg will have better ideas

Hey I have an update, I replaced the COL's and tried a few different things and learned something. the truck works fine when COL's for the ladder are removed, when I replaced them with COL's with properties etc. the problem reoccurred, wheels disappeared and it seemed like the game was rejecting all of the COL's.. you could walk through the truck again.. Could it be due to the height of the COL for the ladder in the raised position?

im really determined to get this to work but have no clue what the issue is, any help from anyone would be greatly appreciated

SECOND UPDATE: I did another test with the ladder COL's, the COL when the ladder is up is what is causing the issue, the COL for the ladder in the down position works fine. is there a way to get it work? or is there a limit to the size or how high a COL can be?

Try build your collision box from existing original piece like door and reshape it in vertex mode, if you built it yourself, just in case it has something missing. It looks on your pictures of your collision models they're little dark in some areas like they facing wrong. They supposed to be flat shaded with calculated normals, axis reset to the parent

You can also try untick deformable, thats how original R* walk on collision for vehicles is set, it's also less demanding on performance and stability of game. However that setting would also lose colliding with map and other surface objects.

Other than that there is a possibility Collision reaching that high is causing this kind of problems, I never had anything like that to compare.

Tried some different things and ended up getting the COL's for the ladders themselves to work, however the chassis COL is still gone, yet the wheels are fine, will let the player hop over the wheels as if it were a low wall if you attempt to jump on top of the truck.. and the doors also work fine, seems to me that only the chassis COL is broken now, any ideas? I'm going to replace it next and see if I can get it to work

Wait you have a problem with chassis Collision also?... do you mean player walks through it? If player walks through it but it does hit objects like a vehicles and buildings, you going to have to create copy of a chassis Collision and untick deformable, you going to have to have both of them just like boats do, group it before convert to compound.

unfortunately this did not fix my situation.. I also attempted to take a COL from a R* vehicle of similar size and the same issue persists, although the ladder COL, all of the doors, the bumpers and the wheels all work fine..

So you made a copy of a chassis collision, then it has to be flat shaded, because copy doesn't copy that setting, then you have to make sure one of them has a deformable ON, and the other has to have deformable OFF, they both have to have calculated normals and the reset to the parent. Then you select them both, group them and convert to compound.... even you would take original Collision model from something you would still have to make the copy and group them, you only don't do it if your existing Collision with deformable on, is already functioning properly for all functions,

Tried that the exact way you suggested and I still have this issue, I can also report that one other vehicle I made before this truck has the same issue, chassis COL not working however everything else does, it also had a COL in an extra. In an attempt to get the vehicle in a FiveM server, it gave me this error code. https://i.imgur.com/MFrSByF.png

I've also made some other vehicles in between trying to get this truck to work, both of them work fine.. when importing a COL from one of those vehicles and replacing it into the truck, it doesn't fix anything unfortunately. this is the error code its giving me https://i.imgur.com/JPvPJh9.png..

the poly 0 edge part catches my eye.. I can confirm that the "when there are only 12" is referring to the chassis COL..

and a question regarding this, I noticed that the chassis_lowlod COL is the same as the regular chassis COL and I've been replacing/"fixing" the lowlod COL's along with the chassis COL's i.e. I grouped it as two, one with deformable on and one with deformable off just like the chassis COL, could that be what I'm doing wrong?

is this an error of zmodeler export or a bad handling of collision on FiveM? I actually don't know what "FiveM" is and how do they get these error reports (are these error coming from game libraries/executable, or they have their own model loader/validator for .yft files?)

Ok, try another thing, because i had strange problem with collisions in little different way. I had ignored about 4 extras, they grouped from 6 separate extras into 2 and spawned all together. Until i removed one of them, it didn't matter which one. So i chose to remove extra12 coffee cup, bam, mission accomplished, all 6 collisions came back to life in proper intended way....So maybe you can try something similar....IDK if my problem was related to poly limit on some lod or who knows what it was.

I just recently experienced totally random malfunctions due to poly limit reaching max on low lods. I would remove little, but not enough and it would change malfunctions little different. Sometimes player would fall through on entry, like there is no seat dummy, sometimes doors would relocate or player would sit in totally different spot, It would always do same bug until i change poly count. Then if i would remove these lods to test, everything would go to regular state. My second malfunction was related to door placement in hierarchy. While doors were relocated due to poly limits, I moved door component up in hierarchy to test difference, however after i removed lods causing problems, doors cam back to place, but all 4 landing gears (it's plane) would close to center dummy, totally unrelated stuff. I moved door in hierarchy back where it was, landing gears fixed back to normal, and all works fine, i just have to do much better work on lowering lods.

Lessen for me is lods poly count close to max can do completely random malfunctions on any component, so when that starts suddenly happening, lods have to be checked, temporarily removed for testing, or properly adjusted.

Hey, had to set this project aside for awhile but I'm picking it back up now, I found a Rockstar vehicle with Extras that have COL's in perfectly working order, I've exported and re-imported the rockstar model successfully, however when I take those extra COL's and make those the COL's for the ladder, it gives me a message upon export: Multiple collision components given for object "extra_6" I checked the hierarchy, no multiples of anything to be found. After Export: https://gyazo.com/d3895ef7808eb1c23adec68ba4cd25d1when I reimport that model this is what happens: https://gyazo.com/0e9cf0d50fee170af91a0e3ac8173acf

what in the world did I mess up? haha just wanted a ladder that you can walk up

I was able to fix the issue, imported a Rockstar vehicle that had Extras with [COL]'s... I'm thinking my issues stemmed from personal settings with the COL's I was using prior. just throwing that out there for anyone that has a similar issue in the future. thanks for the help guys!